In recent years semiconductor devices and microelectromechanical systems have been fabricated with three-dimensional (3-D) features (e.g., fabricated device features), such as inclined or ramped surfaces using grayscale photolithography. In such examples, the inclined surfaces may be implemented as semiconductor or microelectromechanical device features and/or shapes. To produce such 3-D structures, the grayscale photolithography controls a degree to which a resist layer is exposed to incident light energy. In some known examples, higher intensity exposure removes an increased amount of the resist layer.
However, dimensional process control of inclined or ramped surfaces defined by such processes can be difficult. Typically, measured dimensional or tolerance data to adjust the photolithographic process is not obtained until after die and/or wafer fabrication is completed and, thus, is only available for post-production process adjustments. Further, known measuring techniques to measure features for control purposes can be both time and labor intensive. In particular, some known measuring techniques include use of a profilometer, which can entail relatively long cycle times.
The figures are not to scale. Instead, to clarify multiple layers and regions, the thickness of the layers may be enlarged in the drawings. Wherever possible, the same reference numbers will be used throughout the drawing(s) and accompanying written description to refer to the same or like parts. As used in this patent, stating that any part (e.g., a layer, film, area) is in any way positioned on (e.g., positioned on, located on, disposed on, or formed on, etc.) another part, indicates that the referenced part is either in contact with the other part, or that the referenced part is above the other part with one or more intermediate part(s) located therebetween. Stating that any part is in contact with another part means that there is no intermediate part between the two parts.